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Topic: 6F8G grounding (Read 137 times)

In my Crackatwoa, I rotate through 12AU7, 6SN7, and 6F8G driver tubes with adapters.

To me, the 6F8G sound best, but they are picking up some 60Hz noise in the right channel only, presumably from the top cap, so I end up not using them.

As I move my finger closer to the cap, the noise increases. It also increases with increasing volume. The if I cover the tube with a metal cup and make contact with one of metal volume knobs, the noise completely goes away.

I'm no engineer, and I know the amp isn't designed for this tube, but seems like the cap is picking up power supply noise and isn't properly grounded, any way to fix that so I can use these great tubes? Thanks.

There are actually purpose made shields that fit over old shouldered tubes, but they are pretty hard to find. They are shaped like the tube, split into two halves either vertically or horizontally. You can see them here -

Thanks Doc, I'll scrounge around the internet and see what I can find. And thanks for your suggestions PB, it is not on an exterior wall, but I am going to look into what can be done i.e., grounding the particular outlet.